Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of transformation by Rous sarcoma virus on sugar uptake and activity and the subcellular distribution of hexokinase isozymes in chick embryo fibroblasts were examined. Transformation caused a several-fold increase in the maximum velocity for uptake of 2-deoxyglucose without a significant change in Km. Cytochalasin B (CB), was used to differentiate between the effects of transformation on facilitated diffusion and the nonsaturable (CB-insensitive) mode. Transformation was found to stimulate 2-deoxyglucose transport by both mechanisms, but the increase in transport by the CB-insensitive mode was greater. Transformation enhances the activity of hexokinase, the enhancement being confined to the particulate fraction of the enzyme. Heat-inactivation and electrophoretic mobility studies showed that although hexokinase Type I is the major form in both normal and transformed fibroblasts, there is a significant increase in the proportion of the Type II isozyme in the transformed cells.
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PMID:Transport and phosphorylation of hexoses in normal and Rous sarcoma virus-transformed chick embryo fibroblasts. 21 96

The activities of hexokinase and glucose-6-phosphatase, as well as the in vivo metabolic products of 2-[18F]fluoro-2-deoxyglucose ([18F]FDG) (45 min after an i.v. injection), were determined from several tissues of Rous sarcoma implanted rats. The HK/G-6-Pase ratio was found to be high in brain and tumor, and low in liver with intermediate values for kidney and muscle. In accordance with the measured enzyme activities about 90% of the 18F was found as [18F]FDG-6-P in brain, heart and tumor, whereas most of its was as [18F]FDG in liver and kidney. In addition three minor metabolites, tentatively identified as nucleotide-derivatives of [18F]FDG, were formed. Our results suggest that at least Rous sarcoma tumor effectively converts [18F]FDG to [18F]FDG-6-P and thus PET studies with [18F]FDG can be applied to tumor diagnosis and to quantitative measurement of glucose utilization in tumor tissue according to the model of Sokoloff.
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PMID:Metabolism of 2-[18F]fluoro-2-deoxyglucose in tumor-bearing rats: chromatographic and enzymatic studies. 381 23

In addition to the previously described deoxyribonucleic acid (DNA) polymerase, DNA ligase, DNA exonuclease, and DNA endonuclease activities, purified virions of Schmidt-Ruppin strain of Rous sarcoma virus (SRV) have nucleotides and nucleotide kinase, phosphatase, hexokinase, and lactate dehydrogenase activities. The SRV virions have no glucose-6-phosphate dehydrogenase activity. All enzyme activities, but glucose-6-phosphate dehydrogenase and adenosine triphosphatase, were increased by disruption of the virions. The DNA polymerase, DNA ligase, and hexokinase activities had a higher specific activity in purified virion cores. It is suggested that during assembly virions of SRV may pick up cytoplasmic components which bind to virion proteins. The role of these components in viral replication is not known at present.
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PMID:Enzymes and nucleotides in virions of Rous sarcoma virus. 433 49

Chick-embryo cells, transformed with Rous sarcoma virus, show enhanced rates of sugar transport and glycolysis. Determination of intracellular concentrations of glycolytic intermediates suggests that the enhanced glycolytic flux is due to increased activities of hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), phosphofructokinase, (ATP:D-fructose-1-phosphate 6-phosphotransferase, EC 2.7.1.56), and pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40), and not directly to the increased glucose transport. This conclusion is supported by the finding that the intracellular concentration of free glucose is decreased, rather than increased, in the transformed cells. The present observations suggest that the increased glycolytic flux is related to an increased rate of phosphorylation of glucose, and that hexokinase in the transformed cells is at least partly released from its normal control mechanism involving feedback inhibition by glucose-6-P.
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PMID:Alterations in glucose metabolism in chick-embryo cells transformed by Rous sarcoma virus: intracellular levels of glycolytic intermediates. 437 8

A chloromethyl ketone derivative of lactic acid is a potent inhibitor of glycolysis of Ehrlich ascites tumor cells. It inhibited glycolysis of intact cells by about 50% at 200 microM (100 nmol/mg of protein) while cell-free extracts were inhibited 50% at 50 microM (50 nmol/mg of protein). N alpha-(p-Tosyl)-L-lysine chloromethyl ketone and N alpha-(p-tosyl)-L-phenylalanine chloromethyl ketone inhibited only slightly or not at all at this concentration. The inhibition was localized at the hexokinase and phosphofructokinase steps since these two enzymes added to an inactivated extract restored the glycolytic activity, whereas none of the other glycolytic enzymes did. In fact, addition of pyruvate kinase or lactate dehydrogenase, which stimulated glycolysis, resulted in a more pronounced inhibition. Glycolysis and hexokinase activities in extracts of Rous sarcoma virus transformed cells were considerably more sensitive to the inhibitor than the activities from normal chick embryo fibroblasts. Hexokinase from mouse brain required 50 times higher concentrations for inhibition than the enzyme from mouse Ehrlich ascites tumor cells. Yeast hexokinase was unaffected at all concentrations tested. Since 5,5'-dithiobis(2-nitrobenzoate) protected against the inhibition, the chloromethyl ketone appeared to inhibit by interaction with an essential SH group. A pronounced inhibition of protein kinase activity of plasma membranes of Ehrlich ascites tumor cells was observed in the presence of the chloromethyl ketone. As in the case of glycolysis, the chloromethyl ketone of lactic acid was a more potent inhibitor of protein kinase activity than several other chloromethyl ketones that were tested.
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PMID:Inhibition of hexokinase and protein kinase activities of tumor cells by a chloromethyl ketone derivative of lactic acid. 710 7